Comparison Between Cardiopulmonary Exercise Testing Parameters and Computed Tomography Findings in Patients with Thoracic Sarcoidosis

Abstract

Cardiopulmonary exercise testing (CPET) is a safe and clinically useful method to assess functional capacity and to follow disease progression and the response to treatment in several clinical conditions. We set out to determine the relationship between outcome measures of CPET and high-resolution computed tomography (HRCT) findings in thoracic sarcoidosis. A cross-sectional study was carried out in which 42 nonsmoking outpatients (22 females; median age=46.5years) were evaluated. All the patients underwent pulmonary function tests (PFTs) and CPET. By using CPET, the most probable causes of exercise limitation were separated into respiratory mechanics (n=25) and cardiovascular (n=17). By using HRCT, the following patterns were recorded: predominant nodules (n=18), predominant ground-glass opacity (n=10), and predominant traction bronchiectasis and honeycombing (n=14). Although significant differences have been shown for both PFT parameters and CPET results, only the latter were able to distinguish between patients with ground-glass opacity and patients with traction bronchiectasis and honeycombing on HRCT. A statistically significant difference was found for peak VO(2), breathing reserve, and P(A-a)O(2) when patients with predominant traction bronchiectasis and honeycombing were compared to patients with other HRCT patterns (p<0.0001). There was no statistical difference among the patterns with abnormal CPET and the patterns of abnormalities on HRCT (p>0.05). The functional capacity assessed by CPET was strongly influenced by HRCT patterns in sarcoidosis. Patients with traction bronchiectasis and honeycombing have lower exercise capacity measured by CPET.